Reforming catalyst,its manufacture and use

ABSTRACT

CATALYST FOR THE CONVERSION OF HYDRCARBONS, PARTICULARYL FOR REFORMING REACTIONS HAVING AN ALUMINA AN ALUMINA BASED THE FOLLOWING CONTENTS OF METALS EXPRESSED BY WEIGHT WITH RESPECT TO THE ALUMINA: PLATINUM: FROM 0.005 TO 1% IRIDIUM: FROM 0.005 TO 1% THALLIUM OR INDIUM: FROM 0.05 TO 3%, THE CATALYST MAY FURTHER CONTAIN OPTIONALLY FROM 0.1 TO 10% BY WEIGHT OF A HALOGEN AND UP TO 10% BY WEIGHT OF ZINC OR A ZINC COMPOUND SAID PROPORTIONS BEING ALSO RELATIVE TO THE ALUMINUM WEIGHT.

United States Patent US. Cl. 252-466 PT 11 Claims ABSTRACT OF THEDISCLOSURE Catalyst for the conversion of hydrocarbons, particularly forreforming reactions having an alumina base and the following contents ofmetals expressed by weight with respect to the alumina:

platinum: from 0.005 to 1% iridium: from 0.005 to 1% thallium or indium:from 0.05 to 3 The catalyst may further contain optionally from 0.1 toby weight of a halogen and up to 10% by weight of zinc or a zinccompound said proportions being also relative to the alumina weight.

This invention concerns a new catalyst containing (a) alumina, (b)platinum, (c) iridium and )d) thallium or indium.

This invention also concerns the use of this catalyst in a reformingreaction or in other reactions for the conversion of hydrocarbons suchas those of hydrogenation, dehydrogenation, isomerization oraromatization of hydrocarbons.

For a long time, catalysts have been known which contain platinum, saidmetal being deposited on alumina. More recently, many improvements havebeen made to this type of catalyst based on platinum and aluminum; forexample, it has been proposed to make use of a catalyst containingplatinum and iridium, both metals being deposited on alumina (US. Pat.No. 2,848,377). It has been also suggested (US. Pat. No. 2,814,599) tomake use in reforming operations of a catalyst containing platinum andindium or thallium deposited on alumina. But in spite of theseimprovements and of other improvements which have been proposed up tonow, it is now apparent that the tendency is always to search for newcatalysts based on a platinum, which on the one hand, would result instill higher yields in the reforming reactions as well as in otherhydrocarbon conversion reactions, on

' the other hand, would also have a catalyst life much longer than thatof the previously used catalyst.

To attain such objectives, it has just been now discovered that muchhigher yields are achievable, particularly in the reforming reactions,by using a catalyst based on alumina, which contains simultaneouslyplatinum, ridium and thallium or indium. But it has been chieflydiscovered that, by using a catalyst based on alumina, containingsimultaneously platinum, iridium and thallium or indium, the life of thecatalyst is considerably increased, provided that critical amounts ofthallium or indium are used.

The catalyst according to the invention must contain, by weight withrespect to the catalyst carrier, from 0.005 to 1% of platinum(preferably 0.05 to 0.6%), 0.005 to 1% (and preferably from 0.01 to0.09%) of iridium and 0.05 to 3% of thallium or indium.

Optionally, the catalyst may also contain from 0.1 to 10% and preferablyfrom 0.2 to 5%, by Weight with respect to the catalyst carrier, of ahalogen, such, for example, as chlorine or fluorine. Still optionally,the cataice lyst may also contain up to 10% by Weight of zinc or of aziinc compound, this percentage being expressed as zinc 0x1 e.

The catalyst is prepared according to conventional methods. A methodconsists, for example, of: (a) impregnating the carrier (alumina) bymeans of an aqueous solution of a thallium or indium salt (having avalence of 1 or 2 or 3), for example a nitrate; (b) drying at about C.;(c) calcining under air for a few hours at a temperature from 500 to1000 C., preferably of about 700 C.; and (d) then following with asecond impregnation by means of a solution containing platinum andiridium (for example by means of a solution of hexachloroplatinic acidand hexachloroiridic acid).

Another method consists for example, of impregnating the carrier bymeans of a solution containing simultaneously:

(1) platinum (for example hexachloroplatinic acid) (2) thallium orindium (for example, thallium or indium chloride, bromide, fluoride,sulfate or acetate, or still any other thallium or indium salt solublein water or in hydrochloric acid (thallium chloroplatinate for example)(3) iridium, and optionally (4) chlorine or fluorine.

The three metal elements may be introduced also optionally on thecarrier by carrying out 3 successive impregnations in any order. Forexample, there are introduced:

first, the iridium by means of a solution containing the same,optionally followed by a drying or a calcining step;

then the platinum by means of a solution of for example,

hexachloroplatinic acid, optionally followed with drying and calciningsteps;

finally, the thallium and/or indium, this latter impregnation beingnecessarily followed by drying and then a calcining step at atemperature from about 300 to 700 C.

It must be understood that the order of the above mentioned impregnationis not obligatorily and may be different if desired.

Of course any platinum, iridium, indium or thallium compound, aspreviously proposed for taking part in a catalyst composition on analumina carrier, may also be used. There will not be given any detailedlist of such compounds. The types of alumina which can be used in suchcatalysts, particularly in the reforming catalysts, are also well knownin the art.

It is known that the reforming reactions are generally carried out at atemperature from about 450 to 580 C., under a pressure from about 5 to20 kg./cm. the hourly reaction rate being from 0.5 to 10 volume ofliquid charge (naphtha distilling between about 60 C. and 220 C.) pervolume of catalyst.

When the obtained catalysts are used in chemical reac tions other thanreforming, the operating conditions and the composition of the catalystwill be adjusted in a known manner so as to be adapted to the new use.For example, in the case of a simple hydrogenation, it is preferred tooperate between 200 and 400 F. with a catalyst having little or nohalogen content; for isomerization, catalysts with a high chlorine orfluorine content, for example 5 to 10% by weight or even more, arepreferred, the temperatures being advantageously from to 400 C.

The following examples are given for purposes of illustration and arenot intended to limit in any way the scope of the invention.

3 EXAMPLE 1 There is treated a naphtha having the followingcharacteristics:

ASTM distillation C 80-160 Composition:

Aromatic hydrocarbons percent by weight 7 Naphthenic hydrocarbons do 27Paraflinic hydrocarbons .do.. 66 Octane number clear researc About 37Average molecular weight 110 This naphtha passes with recycled hydrogenover two catalysts A and B, containing 0.2% of platinum and 0.05% ofiridium by weight with respect to the carrier which is an alumina havinga specific surface of 240 mP/g. and a porous volume of 57 cc./g.; thechlorine content of catalysts A and B is 1%. Catalyst A further contains0.5% of thallium and catalyst B further contains 0.5 of indium (byweight with respect to the carrier).

Catalysts A and B have been prepared by adding to 100 g. of alumina, 100cc. of an aqueous solution containmg:

1.90 g. of concentrated HCl (d.=1.19),

8 g. of an aqueous solution of chloroplatinic acid with a 2% platinumcontent by weight,

2.18 g. of a chlororidic acid solution with a 2.3 by

weight content of iridium, and

1.06 g. of thallium nitrate for catalyst A, or

1.87 g. of indium nitrate for catalyst B.

Specific gravity at 20 C.

0.2% of platinum 0.05% of iridium 0.5% of thallium (catalyst A) or 0.5of indium (catalyst B) 1.16% of chlorine.

The obtained catalysts A and B have a specific surface of 230 m./ g. anda pore volume of 54 cc. g.

The operation is conducted so as to obtain a clear octane number of96.2.

The experimental conditions are as follows:

Pressure --bars..- 20 Temperature C- 490 Ratio H /hydrocarbon (moles)Naphtha weight/ catalyst weight/hour 3 Table I below gives for the twocatalysts A and B the yield of C and the hydrogen percent contained inthe recycled gas when the research octane number has been obtained.

TABLE II Recycled gas, percent Yield 05 H:

Catalyst- There are thus obtained, by use of catalysts C and D, resultswhich are slightly inferior to those respectively obtained withcatalysts A and B.

EXAMPLE 2 Table III shows that at mid-run, with the respective use ofthe catalysts C and D, the yields of C and the hydrogen percentcontained in the recycled gas are substantially lower than the yield ofC and the hydrogen percent contained in the recycled gas, as obtained bythe use of the catalysts A and B.

TABLE III Recycled Yield 0 gas, percent mid-run H ,mid-run cocoon m s-2CTN-MU! on com EXAMPLE 2A Example 2 is repeated with the use, on the onehand, of catalysts A and B containing:

0.20% of platinum 0.05 of iridium 0.03% of thallium (catalyst A or 0.03%of indium (catalyst B 1.16% of chlorine and by using, on the other hand,catalysts A and B containing:

0.20% of platinum 0.05 of iridium 3.5% of thallium (catalyst A or 3.5 ofindium (catalyst B 1.16% of chlorine.

Table IV below shows that, at mid-run, with the use of catalysts A A Band B the yield C and the hydrogen percent contained in the recycled gasare substantially similar to those obtained with the use of catalysts Cand D which contain neither thallium nor indium.

TABLE I TABLE IV g sRgcycltlalcz Y m C Recycled a erce ie 3 gas, percentYield 0 H2 mid-run H2, mid-run Catalyst- A 82. 6 82. 8 81. 7 82. 3 B 82.3 82. 6 81. 8 82. 1 iii? EXAMPLE 1A 8 This example is not part of theinvention but is only given for purpose of comparison.

Example 1 is repeated with the use of two catalysts C and D which do notcontain iridium. The other characteristics of catalysts C and and D arethose of catalysts A and B used in Example 1, except that thecompositions of the metal elements vary slightly so that the total con-Examples 2 and 2A thus show that the catalyst life is greater for thecatalysts containing alumina, platinum, iridium and thallium or indium,provided that critical amounts of thallium or indium are used.

What we claim as this invention is:

1. A catalyst containing:

(a) alumina;

(b) from 0.005 to 1% by weight of platinum with respect to the alumina;

(c) from 0.005 to 1% of iridium by weight with respect to the alumina;

(d) from 0.05 to 3% by weight, with respect to the alumina, of a metalselected from the group consisting of thallium and indium.

2. A catalyst according to claim 1 further containing from 0.1 to of ahalogen by weight, with respect to the alumina.

3. A catalyst according to claim 1, further containing less than 10% byWeight, with respect to the alumina, of zinc or of a zinc compound,expressed as zinc oxide.

4. A catalyst according to claim 2, further containing less than 10% byweight, with respect to the alumina, of zinc or of a zinc compound,expressed as zinc oxide.

5. A catalyst as defined by claim 1, said metal being thallium.

6. A catalyst as defined by claim 1, said metal being indium.

7. A catalyst as defined by claim 1, containing 0.05- 0.6% by weight ofplatinum with respect to the alumina.

8. A catalyst as defined by claim 1, containing 0.01 0.09% by weight ofindium with respect to the alumina.

9. A catalyst as defined by claim 7, containing 0.01- 0.09% by weight ofindium with respect to the alumina.

10. A catalyst according to claim 3, wherein said halogen is chlorine orfluorine in a percent by weight of 0.2- 5% based on the alumina.

11. A catalyst according to claim 1, containing:

(a) alumina;

(b) 0.05-0.6% by weight of platinum with respect to the alumina;

(0) 0.01 009% by weight of indium with respect to the alumina;

(d) 0.2-5% by weight of a halogen selected from the group consisting ofchlorine and fluorine with respect to the alumina;

(e) less than 10% by weight, with respect to the alumina, of zinc or ofa zinc compound, expressed as zinc oxide.

References Cited UNITED STATES PATENTS 2,814,599 11/1957 LeFrancois etal. 252466 Pt 2,848,377 8/1958 Webb 252466 Pt 2,914,464 11/ 1959 Burton252442 3,696,167 10/ 1972 Iuguin et al 252466 Pt DANIEL E. NYMAN,Primary Examiner A. P. DEMERS, Assistant Examiner US. Cl. X.R.

